# US 8,543,264 B1 · Aircraft system and method for selecting aircraft gliding airspeed during loss of engine power > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,543,264 B1 - Document ID: US8543264B1 - Status: Granted - Kind: B1 - Application number: 13/449,953 - Filed: 2012-04-18 - Granted: 2013-09-24 - Earliest claimed: 2012-04-18 - Assignees: Honeywell International Inc. - Applicants: Jan Tomas - Inventors: Jan Tomas - Web page: https://patentgrep.com/patent/US8543264B1 ## CPC - G05D 1/105: {specially adapted for unpowered flight, e.g. glider, parachuting, forced landing (parachutes per se B64D17/00)} - G05D 1/106: {Change initiated in response to external conditions, e.g. avoidance of elevated terrain or of no-fly zones} - G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES ## Abstract A method and aircraft system are provided for determining an optimal gliding speed that maximizes gliding distance of the aircraft upon engine failure, and comprises calculating the optimal gliding speed from a speed polar curve, true airspeed, heading, and vertical wind speed. The polar curve may be constructed with consideration of the aircraft center of gravity and weight. The calculated gliding speed, which may be restricted to a threshold, is provided to the pilot and optionally to an autopilot. The method is repeated periodically, or if the wind vertical or horizontal velocities exceed a threshold for a predetermined period of time. ## Claims ### Claim 1 An aircraft system within an aircraft having one or more engines, the aircraft system comprising: a first sensor configured to determine a true speed of the aircraft; a second sensor configured to determine a vertical wind speed; a processor coupled to the engines and the first and second sensors, and configured to: determine that the engine has lost the ability to provide thrust; provide a center of gravity and a weight of the aircraft; adjust a speed polar curve considering the center of gravity and weight; calculate an optimal gliding speed for maximizing gliding distance from the speed polar curve, the true airspeed, heading, and the vertical wind speed, if at least one of a change of a vertical wind speed or a change of a horizontal wind speed exceeds a threshold for a period of time; provide the optimal gliding speed to a pilot of the aircraft as a selected gliding speed; and repeat the calculation. ### Claim 2 (depends on 1) The aircraft system of claim 1 wherein the speed polar curve is provided by the manufacturer of the aircraft. ### Claim 3 (depends on 1) The aircraft system of claim 1 further comprising an autopilot, wherein the processor is further configured to: provide the selected gliding speed to the autopilot that causes the aircraft to assume the gliding speed. ### Claim 4 (depends on 1) The aircraft system of claim 1 wherein the processor is further configured to: prevent the selected gliding speed from exceeding a threshold airspeed. ### Claim 5 (depends on 1) The aircraft system of claim 1 wherein the processor is further configured to: periodically repeat the calculation of the optimal gliding speed. ### Claim 6 An aircraft system on board an aircraft having one or more engines, the aircraft system providing a recommended gliding speed for achieving a maximum gliding distance upon failure of the engines to provide thrust, the aircraft system comprising: a display; and a flight director configured to: determine a true airspeed of the aircraft; determine a vertical wind speed; determine that the engine has lost the ability to provide thrust; provide a center of gravity and a weight of the aircraft; adjust the speed polar curve considering a center of gravity and weight; calculate an optimal gliding speed for maximizing gliding distance from the speed polar curve, the true airspeed, and the vertical wind speed, if at least one of a change of a vertical wind speed and a change of a horizontal wind speed exceeds a threshold for a period of time; and display the optimal gliding speed on the display. ### Claim 7 (depends on 6) The aircraft system of claim 6 wherein the speed polar curve is provided by the manufacturer of the aircraft. ### Claim 8 (depends on 6) The aircraft system of claim 6 further comprising an autopilot coupled to the flight director, the autopilot configured to: cause the aircraft to assume the optimal gliding speed. ### Claim 9 (depends on 6) The aircraft system of claim 6 wherein the flight director is further configured to: prevent the optimal gliding speed from exceeding a threshold airspeed. ### Claim 10 (depends on 6) The aircraft system of claim 6 wherein the flight director is further configured to: periodically repeat the calculation of the optimal gliding speed. ### Claim 11 A method for determining an optimal gliding speed for maximizing gliding distance for an aircraft having one or more engines that have lost all thrust, comprising: determining a true airspeed of the aircraft; determining a vertical wind speed; determining that the engines have lost all thrust; providing a center of gravity and a weight of the aircraft; adjust a speed polar curve considering the center of gravity and weight; calculating an optimal gliding speed for maximizing the aircraft gliding distance from the speed polar curve for the aircraft, the true airspeed, heading, and the vertical wind speed, if at least one of a change of an aircraft vertical velocity and a change of a horizontal wind speed exceeds a threshold for a period of time; and provide the optimal gliding speed to a pilot of the aircraft. ### Claim 12 (depends on 11) The aircraft system of claim 11 further comprising: providing the optimal gliding speed to an autopilot that causes the aircraft to assume the gliding speed. ### Claim 13 (depends on 11) The aircraft system of claim 11 further comprising: preventing the calculated gliding speed from exceeding a threshold airspeed. ### Claim 14 (depends on 11) The aircraft system of claim 11 further comprising: periodically repeating the calculation of the optimal gliding speed.